Fever is an important part of the systemic inflammatory response, allowing both immune system activation and a potential slowing of pathogen growth.
Fevers are caused by inflammatory mediators, such as vasoactive amines, being released throughout the entire body, and complement system activation, causing the dilation of blood vessels and increasing capillary permeability. The synthesis of prostaglandin E2 causes the hypothalamus to raise body temperature – this can move the growth temperature out of the optimum for the pathogen, slowing its growth. LPS and cytokines are also involved in the activation of a fever response.